Definition
A sheet metal forming process in which heat is applied to the metal during the dimpling operation to make it more workable, allowing it to be shaped around a flush rivet hole without cracking. Thermal dimpling is used on harder or thicker aluminum alloys, magnesium, and titanium that would crack if cold-dimpled.
Plain English
Pressing a small cone-shaped depression into a sheet of metal around a rivet hole while heating the metal so it can stretch without cracking. The depression lets a flush rivet sit level with the surface.
Context Anchor
Seen in aircraft sheet-metal repair and structural maintenance when preparing holes for flush rivets, especially in metal that may crack if formed cold.
Derivation
Thermal means relating to heat, from the Greek therme. A dimple is a small indentation. So thermal dimpling literally means making a small indentation while heat is applied. The name describes the process directly.
Why Pilots Care
Flush rivets on the outside of an aircraft give a smooth surface that reduces drag. If those rivet holes are dimpled incorrectly and crack, the skin loses strength and the rivet seal can fail. Thermal dimpling is how that work is done correctly on tougher metals.
Grounding Statement
Picture a heated forming tool pressing around a drilled hole until the metal gently takes the shape needed for a flat rivet head.
Intuition Check
Thermal dimpling does not mean unwanted dents caused by heat. It means a controlled maintenance process that uses heat to form the metal correctly.
Example Sentence 1
The technician used thermal dimpling on the magnesium skin panel because cold dimpling would have caused the metal to crack around the rivet holes.
Example Sentence 2
Thermal dimpling allowed the repair patch to be installed without distorting the thin aluminum sheet.